Chain saw



FIG. 1 is a right side view of the ornamental appearance of the chain saw;

FIG. 2 is a left side view of the chain saw shown in FIG. 1;

FIG. 3 is a top view of the chain saw shown in FIG. 1;

FIG. 4 is a bottom view of the chain saw shown in FIG. 1;

FIG. 5 is a front left perspective view of the chain saw shown in FIG. 1;

FIG. 6 is a right rear perspective view of the chain saw shown in FIG. 1; and,

FIG. 7 is a front left perspective view of the chain saw shown in FIG. 1.

Any surfaces of the design not shown, including interior or bottom surfaces, form no part of the claimed invention. Moreover, the chain and bar form no part of the claimed invention.

The broken lines shown in the drawings represent unclaimed portions of the chain saw and form no part of the claimed design. 

I claim the ornamental design for a chain saw, as shown and described. 